Effects of aqueous polymeric surfactants on silicone-hydrogel soft- contact-lens wettability and bacterial adhesion of Pseudomonas aeruginosa

Prevention of Pseudomonas aeruginosa binding to soft-contact lenses (SCLs) may curtail sight-threatening microbial keratitis. Substrate surface wettability is known to modulate adhesion of P. aeruginosa. This study investigates the use of aqueous alkoxylate block co-polymer surfactants for enhanced wettability and antibacterial adhesion of SCLs under leaching conditions. Specifically, Pluronic(R) F127 (PF) and three ethylene oxide-butylene oxide (EOBO) surfactants were studied with four commercially available silicone-hydrogel contact lenses: Pure Vision(TM), Acuvue Advance(TM), Acuvue Oasys(TM) and O(2)Optix(TM). Dilute aqueous PF and EOBO surfactants impregnated all four soft-contact lenses, as demonstrated by surface-tension decline for leached surfactant. For PE surfactant, significant surface-wettability improvement upon rinsing occurred only after overnight leaching. EOBO surfactant showed a similar pattern with O(2)Optix(TM) lenses. EOBO-pretreated Pure Vision(TM) lenses, however, showed fast leaching and a significant change in surface energy towards improved wettability. Adhesion assays of P. aeruginosa displayed a small decrease in the binding rate of PAK bacteria for EOBO-pretreated Pure Vision(TM) lenses, but not for EOBO-pretreated O(2)Optix(TM) lenses. P. aeruginosa strain-PAO1 bacteria adhesion to all lenses was independent of surface wettability. Despite the ability of polymeric surfactants to lower advancing contact angles under leaching conditions, increased lens wettability is not a universal panacea for antifouling of soft-contact lenses. (C) 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.